[FieldTrip] simulated/sample data set for beamforming

[Alexander Nakhnikian]

Hi Hassan,

I also got some strange results from beamforming, although I was using 
DICS, not LCMV.  I'm working with EEG data so I don't know if we're 
using the same recording setup.  Jan-Mathijs suggested that there might 
be problems with the forward model that are influencing the shape of the 
beamformer.  You can look at our exchange if it's still in your inbox.

Regarding modeling, I think fieldtrip has programs to simulated sensors 
given a particular dipole distribution but I haven't used them.  Another 
approach would be to save the leadfields and apply them to a simulated 
matrix of source-level oscillators.  Set most of the "sources" to random 
noise and place sinusoids with a known frequency and high SNR at only a 
few locations (don't use identical oscillators for each source since 
beamformers lose spatial resolution for strongly correlated sources).  I 
haven't tried this in fieldtrip, but I was able to do it with brainstorm 
and the "dipoles" showed up at the correct locations when I applied an 
inverse model to the simulated sensor data.

Best,

Alexander

On 6/10/16 8:57 AM, Hassan Aleem wrote:
> Hi all,
>
> I have a pipeline for beamforming but I am getting unexpected results 
> from my own data, for the sake of sanity I wanted to run some 
> simulated data to see what I get. I am looking to do a 
> timelockanalysis with the LCMV method, so can't use the tutorial data. 
> Would appreciate any help!
>
> Best,
>
> Hassan
>
>
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-- 
Alexander Nakhnikian, Ph.D.
Postdoctoral Fellow
Clinical Research Training Program
VA Boston Healthcare System
Harvard Medical School

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